Instantiating a track

I need help instantiating a "Track".

Eventually, I'd like to have an array of gameobjects that the game will randomly draw from to build a track for the player to follow.

Instead of player movement, I have this track move (the illusion of always running) towards the camera.

(In this case, (0,0,-2)).

I have a simple plane on top of a empty collision cube moving at 2 units a second. The plane is 10 units long--how can I instantiate the next plane so that there's no gap between sections of the track? Right now I'm toying with InvokeRepeating but I don't think unity is accurate enough to do it EXACTLY every 2.5 seconds which causes me to see gaps between the sections of track.

Any pearls of wisdom?